Many machines for making drip coffee or American coffee currently available on the market essentially comprise a water boiler, a percolating chamber, where a paper filter can be positioned and the load of loose coffee grounds being placed on the filter, and a carafe for collecting the percolated coffee, the carafe being positioned below the filter.
The boiler supplies water to the percolating chamber, where by the effect of its own weight the water percolates through the load of loose coffee grounds and the resulting percolated coffee is collected in the carafe.
These drip coffee machines offer the undeniable advantage of being simple in construction with extremely limited production costs.
However, one of the factors that can hinder an even more widespread commercial distribution of such machines lies in the fact that as they have a strong tendency to get dirty with residue retaining liquid from load of spent coffee grounds, they require frequent and meticulous manual cleaning to keep them operating correctly.
The need to replace and dispose of the paper filter after each use also involves negative environmental impacts.